textproduct: Albany

WHAT HAS CHANGED

The Flood Watch for Dutchess and Litchfield Counties was canceled.

We continue to monitor a corridor of rain that will likely become focused around I-90 in the Mohawk Valley, Capital District into western New England tonight into Tuesday morning. Periods of moderate to locally heavy rain can result in poor drainage flooding in urban and low-lying areas and reduced visibility during the Tuesday morning commute.

KEY MESSAGES

1) Periods of showers centered around the I-90 corridor tonight into Tuesday morning will likely produce moderate rain at times. This can result in minor flooding of urban and poor drainage areas during the Tuesday morning commute.

2) Temperatures trend above normal Thursday and Friday with chances for showers and thunderstorms returning Thursday and especially Friday.

DISCUSSION

KEY MESSAGE 1...

Latest sfc observations and RAP analysis show a dew point boundary stalled around the I-90 corridor with high pressure centered in the Gulf of Maine and weak southeasterly flow aloft maintaining warm air and moisture advection across the boundary. This also allowed light showers to remain across much of eastern NY and western New England tonight but latest NYS mesonet and ASOS observations show rainfall rates have light and not leading to any flooding concerns. As a weak wave of low pressure tracks along this boundary through early Tuesday morning with PWATs remaining over 1.50" and freezing levels over 12kft, hi res guidance shows rain become more organized and turning steady/moderate in intensity at times. The mean cloud layer wind even becomes oriented parallel to the stalled east to west boundary, suggesting potential for backbuilding rain; however, instability is nearly non-existent which should limit rainfall rates. Regardless, latest HREF QPF probability matched mean (PMM) shows a narrow corridor of 0.50 to 1.75 inches of rain centered from the Mohawk Valley into the Capital District and parts of southern VT and western MA between the 6-hrly windows from 06 - 12 UTC and 12 - 18 UTC today. There is even a 10 to 30% chance (even localized 50% chance) for 1" of QPF in the 3-hrly PMM from 06 - 15 UTC today. We therefore collaborated with neighboring WFOs to raise QPF amounts late tonight into tomorrow morning to show a region of 0.50 to 1.75" in these areas with QPF amounts decreasing to the north and south of the I-90 corridor. Latest flash flood guidance remains quite high (1.5 to 2" in 1 hour and 2 to 2.50" in 3 hour) so not expecting widespread flooding issues but there is a low to medium chance for localized flooding in urban and poor drainage areas early Tuesday morning, especially in typical flood prone areas. Motorists should allow extra time to reach their destination for today's morning commute as well given the moderate to locally heavy rain potential.

The heaviest rain should wind down by 15 - 18 UTC as the wave of low pressure exits into New England and high pressure from northern New England builds southward. This will allow clouds to give way to increasing sun from north to south this afternoon with clouds clearing overnight.

KEY MESSAGE 2...

High pressure will be in control tomorrow giving us plenty of sunshine with temperatures trending slightly above normal. Temperatures and humidity continue trending upwards for Thursday and Friday as high pressure slides off shore allowing southwesterly return flow to develop. Heat index values will need to be monitored Thursday as there is a low chance that temperatures in valley areas exceed 90. Such warm temperatures combined with increased humidity values will present a low chance for heat advisory criteria (heat index values 95F or higher) in this areas. While temperatures and humidity will be similar into Friday, increased cloud coverage from an approaching cold front looks to lower chances for hitting heat advisory criteria in valley areas. Otherwise, a few isolated to scattered showers and storms are possible Thursday afternoon as a weak pre-frontal trough and a few shortwaves from the mid- Atlantic approach. Friday features a higher chances for more widespread showers and thunderstorms as a stronger trough and sfc cold front track through the Northeast.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Light showers continue at ALB, PSF and GFL this morning as a boundary remains stalled around the I-90 corridor. Vis likely vary between MVFR and IFR through 15 - 18 UTC at ALB and PSF where rain will likely be steadiest. Lighter rain at GFL and POU should support VFR vis but occasional MVFR vis is possible during any steadier periods. Otherwise, expecting MVFR cigs to persist at ALB, PSF, and POU with mainly VFR vis at GFL.

Vis likely improve to VFR by 18 - 19 UTC at all terminals as rain exits from northwest to southeast with PSF the last to see the rain end. Ceilings should then improve from MVFR back to VFR by late afternoon as high pressure builds into the region. Confidence is low to medium in patchy fog developing after 06 UTC given daytime rain and clearing skies overnight with the highest confidence at ALB and PSF where the most rain should occur.

North to northeast winds around 5-9kts this morning into the afternoon. A few gusts of 15-20 KT could occur at KPSF Tuesday afternoon. Winds turn light after 00 UTC.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Scattered SHRA...TSRA. Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Friday: High Operational Impact. Likely SHRA...TSRA. Friday Night: Low Operational Impact. Slight Chance of SHRA. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.